Question

Three charged capacitors, C1= 18
μF, C2 = 28 μF, and C3 = 47 μF, and two open switches, S1 and S2,
are assembled into a network with initial voltages and polarities,
as shown. Final status of the network is attained when the two
switches, S1 and S2, are closed. The final charge on capacitor C3,
in mC, is?